A 49-year-old nurse has been charged with eight counts of first-degree murder in connection with the deaths of eight elderly residents of long-term care facilities in Woodstock and London.

Speaking a news conference on Tuesday morning, Woodstock Police Chief Bill Renton told reporters that the investigation into the murders began on Sept. 29, 2016 after officers received information about a nurse’s possible involvement in the deaths of several patients at care homes in the area.

“As you can imagine this disclosure caused us to immediately assess the information and muster the necessary resources to ensure a thorough investigation of the facts,” Renton said.

The multi-jurisdictional case, which included investigators with the London Police Service and Ontario Provincial Police, ultimately led to the arrest of former Woodstock nurse Elizabeth Tracey Mae Wettlaufer on Monday night.

According to investigators, the deaths occurred over a seven-year period between August 2007 and August 2014.

The elderly patients, who ranged in age from 75 to 96, were killed after being administered a drug, police confirmed.

“We are not in a position at this time to comment further on the specifics of the drug as it forms part of the evidence that is before the courts,” OPP Det.-Supt. Dave Truax told reporters at Tuesday’s news conference.

Investigators would not comment on a possible motive.

Seven victims were residents at the Caressant Care centre in Woodstock and one victim was a patient at the Meadow Park long-term care facility in London.

The patients have been identified as James Silcox, 84, Maurice Granat, 84, Gladys Millard, 87, Helen Matheson, 95, Mary Zurawinski, 96, Helen Young, 90, Maureen Pickering, 79 and Arpad Horvath, 75.

In a statement, the family of one of the victims, James Silcox, said their loved one was a “compassionate and loving human being” who left behind six children, 13 grandchildren, 14 great-grandchildren and one great-great-grandchild.

“We ask that all family members be permitted the time to grief once again in private,” the statement said.

In a written statement sent to CP24, a spokesperson for Caressant Care said staff at the facility are "cooperating fully" with the police investigation.

According to the statement, Wettlaufer left the long-term care home two and a half years ago.

"We remain in regular contact with the Ministry of Health and Long-Term Care. Our highest priority is to continue to provide for the physical, social and spiritual needs of our residents, and that remains our focus. We deeply regret the additional grief and stress this is imposing on the families involved," Lee Griffi, a communications manager for the facility, said in the statement.

"We are determined to avoid compromising the police investigation in any way and are therefore unable to provide any additional comment at this time."

According to a registry online, Wettlaufer resigned from the College of Nurses on Sept. 30, 2016.

Police said Tuesday that the investigation is ongoing.

“I am not going to speculate whether there will be any additional charges. What I can tell you is that we are confident at this time that all the victims have been identified and their families have been notified,” Renton said.

Renton offered his condolences to the families of the victims.

“On behalf of every police agency represented here today, we extend our deepest sympathies to the families of those who have suffered this tragic loss,” he said.

“It’s very difficult for a community to have to endure these types of tragic incidents but the community is strong and the community will rally.”

The Canadian Association of Retired Persons (CARP), an organization that advocates on behalf of adults aged 50 and over, said the alleged homicides highlight an “ongoing societal issue of abuse of elderly citizens” but should not be considered a reflection of all the nursing profession.

“CARP recognizes the tremendous care that thousands of nurses and personal support workers provide to seniors living in long term care facilities across Canada,” Anthony Quinn, the director of public affairs at CARP, said in a statement. “This tragic crime is in no way reflective on those who endeavor to provide comfort and dignity to seniors in their final days."

Anyone with information about the case is asked to call Woodstock police at 519-537-2323 or Crime Stoppers at 1-800-222-8477.

Wettlaufer appeared at the Ontario Court of Justice in Woodstock on Tuesday morning and has been remanded into custody.